1. Field of the Invention
The invention relates to the production of monocrystals via the Verneuil technique and somewhat more particularly to an apparatus for producing relatively large diameter monocrystals while maintaining heatequilibrium conditions about the growing crystals during and after the growth process.
2. Prior Art
My above reference U.S. patent applications (which correspond to German DOS 2,014,203 and German DOS 2,057,782) generally disclose a novel arrangement for producing monocrystals via the Verneuil technique wherein a gas deflector unit is positioned within a suitable furnace so that the flame gases which impinge on the growing crystal are deflected away from the crystal in such a manner that the flame gases substantially only contact the dome or growth front of the crystal on which additional crystal forming material is melted and solidified during the process. In this type of arrangement, the flame or burner which produces the flame gas is positioned in vertical alignment above the crystal being grown so that the lateral deflection of the flame gases occur substantially directly below the upmost surface of the dome or growth front of the crystal. The flame gases flow laterally along the gas deflection unit and emerge from the furnace via a suitable gas outlet. The gas deflection unit within this type of arrangement is positioned within a heat-insulating member, which may form a part of the furnace encompassing the gas deflector unit. The gas deflector unit is of a relatively large mass and formed of a high heat capacity material in relation to the heat capacity of the crystal being grown, such as sintered aluminum oxide. This type of deflector unit thus absorbs a large amount of heat during the growth process and functions as a heat reservoir after the flame is shut off so that the grown crystal is not subjected to any sudden temperature variation. In other words, the grown crystal is in thermal equilibrium with such a gas deflector unit even after the flame has been terminated. Additional details of such arrangements may be obtained from the above referenced patents as well as from the following description of exemplary embodiments of the present invention.